1. Field of the Invention
This invention relates to vibration damping devices used in automotive engine mounts, etc., and especially to those vibration damping devices that are equipped with a separate stopper member that limits the amount of relative displacement in the axis-perpendicular direction of the first mounting member and the second mounting member.
2. Description of the Related Art
Conventionally, a vibration damping device is known as a kind of vibration damping connector or vibration damping support that is placed between the components that make up the vibration transmission system and that provides a vibration damping connection between those components. This vibration damping device, for example as stated in Japanese Unexamined Patent Publication No. JP-A-2010-174957, features a structure that, through its main rubber elastic body, elastically connects a first mounting member that is configured to be attached to one side of the components that constitute the vibration transmission system and a second mounting member that is configured to be attached to the other side of the components that constitute the vibration transmission system.
A housing recess is also formed on the inner circumference of the second mounting member and a separate stopper member is positioned in the housing recess so that the amount of relative displacement in the axis-perpendicular direction of the first mounting member and the second mounting member is limited by contact via the stopper member.
With the vibration damping device described in JP-A-2010-174957, it is necessary to keep the stopper member from falling out of the housing recess in the vibration damping device before the device is installed on the vehicle, etc. Accordingly, in JP-A-2010-174957, the stopper member is situated in such a way that it is compressed against the inner circumferential surface of the housing recess, and held within that housing recess by the recovery force of the stopper member itself.
However, with the structure described in JP-A-2010-174957, since resistance of the stopper member to falling out of the housing recess is created through the frictional resistance based on the recovery force of the stopper member, there was still a concern of the stopper member falling out due to vibration during transport, etc. Also, if the stopper member is pressed against the inner circumferential surface of the housing recess in advance, there is a concern that a large dynamic spring constant will be produced in the axis-perpendicular direction of the overall vibration damping device by tightening in of the main rubber elastic body or by the spring component of the stopper member, and the vibration damping performance might thus deteriorate.